/*
** $Id: liolib.c,v 2.73.1.4 2010/05/14 15:33:51 roberto Exp $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/


#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define liolib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"
#include "lrotable.h"


#define IO_INPUT    1
#define IO_OUTPUT   2
#define IO_STDERR   0

#if LUA_OPTIMIZE_MEMORY != 2
#define LUA_IO_GETFIELD(f)  lua_rawgeti(L, LUA_ENVIRONINDEX, f)
#define LUA_IO_SETFIELD(f)  lua_rawseti(L, LUA_ENVIRONINDEX, f)
#else
#define LUA_IO_GETFIELD(f)  lua_rawgeti(L, LUA_REGISTRYINDEX, liolib_keys[f])
#define LUA_IO_SETFIELD(f)  lua_rawseti(L, LUA_REGISTRYINDEX, liolib_keys[f])

/* "Pseudo-random" keys for the registry */
static const int liolib_keys[] = {(int) &luaL_callmeta, (int) &luaL_typerror, (int) &luaL_argerror};
#endif

static const char *const fnames[] = {"input", "output"};

static int pushresult(lua_State *L, int i, const char *filename)
{
    int en = errno;  /* calls to Lua API may change this value */
    if (i)
    {
        lua_pushboolean(L, 1);
        return 1;
    }
    else
    {
        lua_pushnil(L);
        if (filename)
            lua_pushfstring(L, "%s: %s", filename, strerror(en));
        else
            lua_pushfstring(L, "%s", strerror(en));
        lua_pushinteger(L, en);
        return 3;
    }
}


static void fileerror(lua_State *L, int arg, const char *filename)
{
    lua_pushfstring(L, "%s: %s", filename, strerror(errno));
    luaL_argerror(L, arg, lua_tostring(L, -1));
}


#define tofilep(L)  ((FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE))


static int io_type(lua_State *L)
{
    void *ud;
    luaL_checkany(L, 1);
    ud = lua_touserdata(L, 1);
    lua_getfield(L, LUA_REGISTRYINDEX, LUA_FILEHANDLE);
    if (ud == NULL || !lua_getmetatable(L, 1) || !lua_rawequal(L, -2, -1))
        lua_pushnil(L);  /* not a file */
    else if (*((FILE **)ud) == NULL)
        lua_pushliteral(L, "closed file");
    else
        lua_pushliteral(L, "file");
    return 1;
}


static FILE *tofile(lua_State *L)
{
    FILE **f = tofilep(L);
    if (*f == NULL)
        luaL_error(L, "attempt to use a closed file");
    return *f;
}



/*
** When creating file handles, always creates a `closed' file handle
** before opening the actual file; so, if there is a memory error, the
** file is not left opened.
*/
static FILE **newfile(lua_State *L)
{
    FILE **pf = (FILE **)lua_newuserdata(L, sizeof(FILE *));
    *pf = NULL;  /* file handle is currently `closed' */
    luaL_getmetatable(L, LUA_FILEHANDLE);
    lua_setmetatable(L, -2);
    return pf;
}


#if LUA_OPTIMIZE_MEMORY != 2
/*
** function to (not) close the standard files stdin, stdout, and stderr
*/
static int io_noclose(lua_State *L)
{
    lua_pushnil(L);
    lua_pushliteral(L, "cannot close standard file");
    return 2;
}


/*
** function to close 'popen' files
*/
static int io_pclose(lua_State *L)
{
    FILE **p = tofilep(L);
    int ok = lua_pclose(L, *p);
    *p = NULL;
    return pushresult(L, ok, NULL);
}


/*
** function to close regular files
*/
static int io_fclose(lua_State *L)
{
    FILE **p = tofilep(L);
    int ok = (fclose(*p) == 0);
    *p = NULL;
    return pushresult(L, ok, NULL);
}
#endif

static int aux_close(lua_State *L)
{
#if LUA_OPTIMIZE_MEMORY != 2
    lua_getfenv(L, 1);
    lua_getfield(L, -1, "__close");
    return (lua_tocfunction(L, -1))(L);
#else
    FILE **p = tofilep(L);
    if (*p == stdin || *p == stdout || *p == stderr)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "cannot close standard file");
        return 2;
    }
    int ok = (fclose(*p) == 0);
    *p = NULL;
    return pushresult(L, ok, NULL);
#endif
}


static int io_close(lua_State *L)
{
    if (lua_isnone(L, 1))
        LUA_IO_GETFIELD(IO_OUTPUT);
    tofile(L);  /* make sure argument is a file */
    return aux_close(L);
}


static int io_gc(lua_State *L)
{
    FILE *f = *tofilep(L);
    /* ignore closed files */
    if (f != NULL)
        aux_close(L);
    return 0;
}


static int io_tostring(lua_State *L)
{
    FILE *f = *tofilep(L);
    if (f == NULL)
        lua_pushliteral(L, "file (closed)");
    else
        lua_pushfstring(L, "file (%p)", f);
    return 1;
}


static int io_open(lua_State *L)
{
    const char *filename = luaL_checkstring(L, 1);
    const char *mode = luaL_optstring(L, 2, "r");
    FILE **pf = newfile(L);
    *pf = fopen(filename, mode);
    return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
}


/*
** this function has a separated environment, which defines the
** correct __close for 'popen' files
*/
static int io_popen(lua_State *L)
{
    const char *filename = luaL_checkstring(L, 1);
    const char *mode = luaL_optstring(L, 2, "r");
    FILE **pf = newfile(L);
    *pf = lua_popen(L, filename, mode);
    return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
}


static int io_tmpfile(lua_State *L)
{
    FILE **pf = newfile(L);
    *pf = tmpfile();
    return (*pf == NULL) ? pushresult(L, 0, NULL) : 1;
}


static FILE *getiofile(lua_State *L, int findex)
{
    FILE *f;
    LUA_IO_GETFIELD(findex);
    f = *(FILE **)lua_touserdata(L, -1);
    if (f == NULL)
        luaL_error(L, "standard %s file is closed", fnames[findex - 1]);
    return f;
}


static int g_iofile(lua_State *L, int f, const char *mode)
{
    if (!lua_isnoneornil(L, 1))
    {
        const char *filename = lua_tostring(L, 1);
        if (filename)
        {
            FILE **pf = newfile(L);
            *pf = fopen(filename, mode);
            if (*pf == NULL)
                fileerror(L, 1, filename);
        }
        else
        {
            tofile(L);  /* check that it's a valid file handle */
            lua_pushvalue(L, 1);
        }
        LUA_IO_SETFIELD(f);
    }
    /* return current value */
    LUA_IO_GETFIELD(f);
    return 1;
}


static int io_input(lua_State *L)
{
    return g_iofile(L, IO_INPUT, "r");
}


static int io_output(lua_State *L)
{
    return g_iofile(L, IO_OUTPUT, "w");
}


static int io_readline(lua_State *L);


static void aux_lines(lua_State *L, int idx, int toclose)
{
    lua_pushvalue(L, idx);
    lua_pushboolean(L, toclose);  /* close/not close file when finished */
    lua_pushcclosure(L, io_readline, 2);
}


static int f_lines(lua_State *L)
{
    tofile(L);  /* check that it's a valid file handle */
    aux_lines(L, 1, 0);
    return 1;
}


static int io_lines(lua_State *L)
{
    if (lua_isnoneornil(L, 1))    /* no arguments? */
    {
        /* will iterate over default input */
        LUA_IO_GETFIELD(IO_INPUT);
        return f_lines(L);
    }
    else
    {
        const char *filename = luaL_checkstring(L, 1);
        FILE **pf = newfile(L);
        *pf = fopen(filename, "r");
        if (*pf == NULL)
            fileerror(L, 1, filename);
        aux_lines(L, lua_gettop(L), 1);
        return 1;
    }
}


/*
** {======================================================
** READ
** =======================================================
*/


static int read_number(lua_State *L, FILE *f)
{
    lua_Number d;
    if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1)
    {
        lua_pushnumber(L, d);
        return 1;
    }
    else
    {
        lua_pushnil(L);  /* "result" to be removed */
        return 0;  /* read fails */
    }
}


static int test_eof(lua_State *L, FILE *f)
{
    int c = getc(f);
    ungetc(c, f);
    lua_pushlstring(L, NULL, 0);
    return (c != EOF);
}


static int read_line(lua_State *L, FILE *f)
{
    luaL_Buffer b;
    luaL_buffinit(L, &b);
    for (;;)
    {
        size_t l;
        char *p = luaL_prepbuffer(&b);
        if (fgets(p, LUAL_BUFFERSIZE, f) == NULL)    /* eof? */
        {
            luaL_pushresult(&b);  /* close buffer */
            return (lua_objlen(L, -1) > 0);  /* check whether read something */
        }
        l = strlen(p);
        if (l == 0 || p[l - 1] != '\n')
            luaL_addsize(&b, l);
        else
        {
            luaL_addsize(&b, l - 1);  /* do not include `eol' */
            luaL_pushresult(&b);  /* close buffer */
            return 1;  /* read at least an `eol' */
        }
    }
}


static int read_chars(lua_State *L, FILE *f, size_t n)
{
    size_t rlen;  /* how much to read */
    size_t nr;  /* number of chars actually read */
    luaL_Buffer b;
    luaL_buffinit(L, &b);
    rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */
    do
    {
        char *p = luaL_prepbuffer(&b);
        if (rlen > n) rlen = n;  /* cannot read more than asked */
        nr = fread(p, sizeof(char), rlen, f);
        luaL_addsize(&b, nr);
        n -= nr;  /* still have to read `n' chars */
    }
    while (n > 0 && nr == rlen);    /* until end of count or eof */
    luaL_pushresult(&b);  /* close buffer */
    return (n == 0 || lua_objlen(L, -1) > 0);
}


static int g_read(lua_State *L, FILE *f, int first)
{
    int nargs = lua_gettop(L) - 1;
    int success;
    int n;
    clearerr(f);
    if (nargs == 0)    /* no arguments? */
    {
        success = read_line(L, f);
        n = first + 1; /* to return 1 result */
    }
    else    /* ensure stack space for all results and for auxlib's buffer */
    {
        luaL_checkstack(L, nargs + LUA_MINSTACK, "too many arguments");
        success = 1;
        for (n = first; nargs-- && success; n++)
        {
            if (lua_type(L, n) == LUA_TNUMBER)
            {
                size_t l = (size_t)lua_tointeger(L, n);
                success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
            }
            else
            {
                const char *p = lua_tostring(L, n);
                luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
                switch (p[1])
                {
                case 'n':  /* number */
                    success = read_number(L, f);
                    break;
                case 'l':  /* line */
                    success = read_line(L, f);
                    break;
                case 'a':  /* file */
                    read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */
                    success = 1; /* always success */
                    break;
                default:
                    return luaL_argerror(L, n, "invalid format");
                }
            }
        }
    }
    if (ferror(f))
        return pushresult(L, 0, NULL);
    if (!success)
    {
        lua_pop(L, 1);  /* remove last result */
        lua_pushnil(L);  /* push nil instead */
    }
    return n - first;
}


static int io_read(lua_State *L)
{
    return g_read(L, getiofile(L, IO_INPUT), 1);
}


static int f_read(lua_State *L)
{
    return g_read(L, tofile(L), 2);
}


static int io_readline(lua_State *L)
{
    FILE *f = *(FILE **)lua_touserdata(L, lua_upvalueindex(1));
    int sucess;
    if (f == NULL)  /* file is already closed? */
        luaL_error(L, "file is already closed");
    sucess = read_line(L, f);
    if (ferror(f))
        return luaL_error(L, "%s", strerror(errno));
    if (sucess) return 1;
    else    /* EOF */
    {
        if (lua_toboolean(L, lua_upvalueindex(2)))    /* generator created file? */
        {
            lua_settop(L, 0);
            lua_pushvalue(L, lua_upvalueindex(1));
            aux_close(L);  /* close it */
        }
        return 0;
    }
}

/* }====================================================== */


static int g_write(lua_State *L, FILE *f, int arg)
{
    int nargs = lua_gettop(L) - 1;
    int status = 1;
    for (; nargs--; arg++)
    {
        if (lua_type(L, arg) == LUA_TNUMBER)
        {
            /* optimization: could be done exactly as for strings */
            status = status &&
                     fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
        }
        else
        {
            size_t l;
            const char *s = luaL_checklstring(L, arg, &l);
            status = status && (fwrite(s, sizeof(char), l, f) == l);
        }
    }
    return pushresult(L, status, NULL);
}


static int io_write(lua_State *L)
{
    return g_write(L, getiofile(L, IO_OUTPUT), 1);
}


static int f_write(lua_State *L)
{
    return g_write(L, tofile(L), 2);
}


static int f_seek(lua_State *L)
{
    static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
    static const char *const modenames[] = {"set", "cur", "end", NULL};
    FILE *f = tofile(L);
    int op = luaL_checkoption(L, 2, "cur", modenames);
    long offset = luaL_optlong(L, 3, 0);
    op = fseek(f, offset, mode[op]);
    if (op)
        return pushresult(L, 0, NULL);  /* error */
    else
    {
        lua_pushinteger(L, ftell(f));
        return 1;
    }
}


static int f_setvbuf(lua_State *L)
{
    static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
    static const char *const modenames[] = {"no", "full", "line", NULL};
    FILE *f = tofile(L);
    int op = luaL_checkoption(L, 2, NULL, modenames);
    lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
    int res = setvbuf(f, NULL, mode[op], sz);
    return pushresult(L, res == 0, NULL);
}



static int io_flush(lua_State *L)
{
    return pushresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
}


static int f_flush(lua_State *L)
{
    return pushresult(L, fflush(tofile(L)) == 0, NULL);
}

#define MIN_OPT_LEVEL 2
#include "lrodefs.h"
#if LUA_OPTIMIZE_MEMORY == 2
const LUA_REG_TYPE iolib_funcs[] =
{
#else
const LUA_REG_TYPE iolib[] =
{
#endif
    {LSTRKEY("close"), LFUNCVAL(io_close)},
    {LSTRKEY("flush"), LFUNCVAL(io_flush)},
    {LSTRKEY("input"), LFUNCVAL(io_input)},
    {LSTRKEY("lines"), LFUNCVAL(io_lines)},
    {LSTRKEY("open"), LFUNCVAL(io_open)},
    {LSTRKEY("output"), LFUNCVAL(io_output)},
    {LSTRKEY("popen"), LFUNCVAL(io_popen)},
    {LSTRKEY("read"), LFUNCVAL(io_read)},
    {LSTRKEY("tmpfile"), LFUNCVAL(io_tmpfile)},
    {LSTRKEY("type"), LFUNCVAL(io_type)},
    {LSTRKEY("write"), LFUNCVAL(io_write)},
    {LNILKEY, LNILVAL}
};

#if LUA_OPTIMIZE_MEMORY == 2
static int luaL_index(lua_State *L)
{
    return luaR_findfunction(L, iolib_funcs);
}

const luaL_Reg iolib[] =
{
    {"__index", luaL_index},
    {NULL, NULL}
};
#endif

#undef  MIN_OPT_LEVEL
#define MIN_OPT_LEVEL 1
#include "lrodefs.h"
const LUA_REG_TYPE flib[] =
{
    {LSTRKEY("close")     , LFUNCVAL(io_close)   },
    {LSTRKEY("flush")     , LFUNCVAL(f_flush)    },
    {LSTRKEY("lines")     , LFUNCVAL(f_lines)    },
    {LSTRKEY("read")      , LFUNCVAL(f_read)     },
    {LSTRKEY("seek")      , LFUNCVAL(f_seek)     },
    {LSTRKEY("setvbuf")   , LFUNCVAL(f_setvbuf)  },
    {LSTRKEY("write")     , LFUNCVAL(f_write)    },
    {LSTRKEY("__gc")      , LFUNCVAL(io_gc)      },
    {LSTRKEY("__tostring"), LFUNCVAL(io_tostring)},
#if LUA_OPTIMIZE_MEMORY > 0
    {LSTRKEY("__index")   , LROVAL(flib)         },
#endif
    {LNILKEY, LNILVAL}
};

static void createmeta(lua_State *L)
{
#if LUA_OPTIMIZE_MEMORY == 0
    luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
    lua_pushvalue(L, -1);  /* push metatable */
    lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
    luaL_register(L, NULL, flib);  /* file methods */
#else
    luaL_rometatable(L, LUA_FILEHANDLE, (void *)flib); /* create metatable for file handles */
#endif
}


static void createstdfile(lua_State *L, FILE *f, int k, const char *fname)
{
    *newfile(L) = f;
#if LUA_OPTIMIZE_MEMORY != 2
    if (k > 0)
    {
        lua_pushvalue(L, -1);
        lua_rawseti(L, LUA_ENVIRONINDEX, k);
    }
    lua_pushvalue(L, -2);  /* copy environment */
    lua_setfenv(L, -2);  /* set it */
    lua_setfield(L, -3, fname);
#else
    lua_pushvalue(L, -1);
    lua_rawseti(L, LUA_REGISTRYINDEX, liolib_keys[k]);
    lua_setfield(L, -2, fname);
#endif
}

#if LUA_OPTIMIZE_MEMORY != 2
static void newfenv(lua_State *L, lua_CFunction cls)
{
    lua_createtable(L, 0, 1);
    lua_pushcfunction(L, cls);
    lua_setfield(L, -2, "__close");
}
#endif

LUALIB_API int luaopen_io(lua_State *L)
{
    createmeta(L);
#if LUA_OPTIMIZE_MEMORY != 2
    /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */
    newfenv(L, io_fclose);
    lua_replace(L, LUA_ENVIRONINDEX);
    /* open library */
    luaL_register(L, LUA_IOLIBNAME, iolib);
    newfenv(L, io_noclose);  /* close function for default files */
#else
    luaL_register_light(L, LUA_IOLIBNAME, iolib);
    lua_pushvalue(L, -1);
    lua_setmetatable(L, -2);
#endif
    /* create (and set) default files */
    createstdfile(L, stdin, IO_INPUT, "stdin");
    createstdfile(L, stdout, IO_OUTPUT, "stdout");
    createstdfile(L, stderr, IO_STDERR, "stderr");
#if LUA_OPTIMIZE_MEMORY != 2
    lua_pop(L, 1);  /* pop environment for default files */
    lua_getfield(L, -1, "popen");
    newfenv(L, io_pclose);  /* create environment for 'popen' */
    lua_setfenv(L, -2);  /* set fenv for 'popen' */
    lua_pop(L, 1);  /* pop 'popen' */
#endif
    return 1;
}
